[Pumping performance of a new piezoelectric pump for drug delivery]

A novel double-chamber series piezoelectric pump has been presented and tested. The pump is a multi-layer circular planar structure, consisting of PMMA (polymethyl methacrylate) pump body, two PZT actuator membranes and three cantilever valves. The PZT actuators are driven at a phase difference of 180 degrees, which is equal to two one-chamber pumps running in series. The output performance depends on the geometrical parameters of the actuator membrane. The prototype pump, fabricated with the PZT membrane 0.18 mm in thickness and 50 mm in diameter of 50 mm, can deliver drug in either direct way (pumping liquid drug) or indirect way (pumping air to extrude liquid drug from a sealed container). The frequency-response characteristic of the two handling methods is of difference. The pump obtains optimum performance at low frequency for liquid as medium, and at high frequency for air as medium. For both the direct delivery and indirect delivery, the maximum flowrate achieved reached up to 220 ml/min and 35 ml/min, respectively; and the maximum backpressure obtained amounted to about 14 KPa and 21 KPa, respectively, at the applied voltage of 80 V with frequency of 20 Hz.